The present invention relates to an apparatus and method of continuously manufacturing security or electronic article surveillance tags. More particularly, the present invention relates to a method and apparatus which form housing cavities in a plastic web, insert resonator strips in the cavities, cover the cavities with lid stock, attach bias strips on the lid stock outer surface and place cover stock over the bias strips and lid stock.
Electronic article surveillance devices such as security tags or labels are placed on products to prevent theft. These devices are often used in retail stores. An activated security tag is placed on an item to sound an alarm at the store exit if the security tag is not deactivated. No alarm will sound if the tag is properly deactivated at the store cash register after the customer has purchased the appropriate item.
The security tag basically comprises a resonator strip mounted loosely to permit movement in a plastic housing. A magnetic bias strip is attached outside this housing and is covered with a plastic layer. When the bias strip is magnetized, it will cause the security tag to be active. The security tag is deactivated by demagnetizing the bias strip.
With the bias strip of the security tag magnetized, the resonator can receive a signal from a transmitter to absorb energy from the transmitter. When the transmitter stops transmitting, the resonator strip vibrates because of its proximity to the magnetized bias strip to transmit its own signal at a set frequency. This signal from the vibrating resonator strip can be picked up by a receiver to set off the alarm. If the bias strip is demagnetized, the resonator strip will not transmit its own signal at the set frequency to set off the alarm.
Conventionally, the security tags are made by cutting plastic styrene sheets and placing the cut sheets in a forming mold. Heat is applied to the sheet while a vacuum pressure pulls the plastic into the mold to conform the sheet to the mold to form housing cavities. Resonator strips cut to length at another manufacturing location or production line are placed in the formed housing cavities. Clear plastic lid stock is cut to shape and placed over the formed styrene sheet to close the cavities with the resonator strips inside. The lid stock and styrene layers are then joined by heat sealing. The bias strips or magnets are then placed on the outer surfaces of the lid stock and secured by an adhesive layer.
In a separate production line, the sheet can be cut into individual labels with the waste material being removed. Additionally, an activation field can be provided to activate the tags. Automatic and manual testing can also be performed in downstream processing.
This conventional manufacturing system cannot be made fully automatic and does not permit use of a single production line to make a finally manufactured security tag. The required operator assistance, coordination of separate production lines and the movement of the respective parts between the separate production lines increases the cost of manufacture and slows production.
An object of the present invention is to provide a method and apparatus for continuously manufacturing security tags which can simply and inexpensively manufacture the security tag in a highly precise manner at high production rates.
Another object of the present invention is to provide a method and apparatus for continuously manufacturing security tags which can make the entire tag in a single production line.
The foregoing objects are basically obtained by an apparatus for continuously manufacturing security tags comprising a first supply for plastic housing material in a continuous web and a plastic former downstream of the first supply for forming housing cavities in the housing plastic material without separating the continuous web. A resonator feeder is downstream of the plastic former and places resonator strips in the housing cavities. A second supply is downstream of the resonator feeder and places lid stock material over open ends of the housing cavities to seal the housing cavities closed with the resonator strips therein. A bias feeder is downstream of the resonator feeder for attaching bias strips to the outer surface of the lid stock material remote from the housing cavities. A third supply is adjacent the bias feeder and places cover stock material over the bias strips and outer surface of the lid stock material.
The foregoing objects are also basically obtained by a method of continuously manufacturing security tags comprising the steps of supplying housing stock material in a continuous web from a first supply station, forming housing cavities in the housing stock material without separation of the continuous web in a plastic forming station located downstream of the first supply station, inserting resonator strips in the housing cavities in a resonator feed station located downstream of the plastic forming station, closing and sealing the housing cavities with the resonator strips therein by placing the lid stock material over open ends of the housing cavities in a second supply station located downstream of the resonator feed station, attaching bias strips to an outer surface of the lid stock material remote from the housing cavities in a bias feed station downstream from the resonator feed station, and placing cover strip material over the bias strips and the outer surface of the lid stock material in a third supply station adjacent the bias feed station.
By forming the apparatus and by performing the method of the present invention in this manner, the security tags can be manufactured simply, precisely, rapidly and inexpensively. Particularly, the apparatus and method permit the entire security tag to be made in a single production line with each of the base materials being provided in large continuous rolls.
Other objects, advantages and salient features of the present invention will become apparent from the following detail description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.